The Effects of Check Dams on the Amount and Pattern of Flood using Hydrological Modeling

Abstract

Abstract In this study, field measurement, spatial information, and HEC-RAS modeling were used to determine changes in the amount and pattern of flow in a waterway due to the construction of check dams. The location map of the structures and their upstream area was prepared in the GIS environment. The flow rate with different return periods was calculated from empirical methods. To simulate the changes in the flow pattern, the HEC-RAS model was calibrated. Flows and corresponding water levels were measured and data at 70% and 30% ratios were used for calibration and validation, respectively. The accuracy of the hydrological model in predicting water elevation was assessed using statistical indicators. The effect of check dams on the flow pattern and time in different discharges was quantitatively calculated and compared with the conditions before construction. The simulation results by HEC-RAS model showed a high correlation between observed and calculated values of flow and water level in the waterway (R2 = 0.96 and RMSE = 0.029). In most structures, the flow velocity increased after passing the structures. In a 2-yr flood, the flow time increased by 82.8 minutes due to the check dams. This time is lower in floods with higher return periods.